The present invention relates to a modular telecommunication jack-type connector, hereafter merely called jack, generally used in telecommunication systems in association with a mating plug-type connector. The modular plug and jack combination is one of the principal components in a cabling system. A 8-pin modular combination comprising a well known RJ-45 male connector or plug as well as a RJ-45 female connector or jack is for instance standardized (I.E.C. 60603) or drafted for both the "Category 5" and "Category 6" connections, i.e. for transmission frequencies of up to 100 MHz and 200 MHz respectively. In these cases, incidence of electrical characteristics, particularly crosstalk effects such as the Near End CrossTalk or NEXT--, is relatively higher at the connections than in other parts of the cabling. The contact wires in the jack and in the plug are the major performance culprits, and the jack is usually designed to compensate these shortcomings. In other words, the jack has to compensate for imbalance created by the electrical contacts both in the plug and in this jack. To this end, the jack includes a crosstalk compensation arrangement as will be described in more detail below.
The present invention more particularly relates to a modular telecommunication jack-type connector comprising a dielectric housing means including a plug-receiving area, a plurality of terminals mounted on the housing means and a crosstalk compensation arrangement, the terminals of said plurality being mounted in parallel into said housing means and each terminal including a spring beam contact portion extending in cantilever fashion within the plug-receiving area, said contact portion having a first end extending to a curved base portion located in the housing means and being coupled to external connections of the modular connector, said crosstalk compensation arrangement comprising metallic plates connected to said terminals, wherein at least one other pair of terminals is associated to plates overlapping each other in parallel planes in order to define a physical capacitor between the associated other pair of terminals.
A classical method to compensating for the electrical anomalies caused by the split pair is the use of a printed board circuit. One or preferably more fixed capacitances are created, e.g. on a printed board circuit, to emulate a crossover effect. Such a jack is already known in the art, e.g. from the European Patent Application EP-A1-0 692 884 filed on Jul. 14, 1994 by MOLEX INCORPORATED (USA) and entitled "Modular connector with reduced crosstalk". Therein, the terminals have, between the first end of the contact portion and the external connection, an intermediate portion with enlarged sections forming metallic surfaces or plates. These surfaces are mounted on opposite sides of an insulating strip or plate creating so the physical capacitor(s) of the crosstalk compensation arrangement.
It is to be noted that other techniques like pair crossover or longitudinal capacitance are also classically used. These are for instance known from the UK Patent Application GB-A-2 298 974 filed on Mar. 14, 1996 by HUBBELL INCORPORATED (USA) and entitled "Crosstalk noise reduction connector for telecommunication system", or from the United States Patent U.S. Pat. No. 5,556,307 filed on Nov. 29, 1994 by THE WIREMOLD COMPANY (USA) and entitled "Modular telecommunication jack assembly". However, the crosstalk compensation obtained by the assemblies disclosed in these latter documents is relatively lower than that obtained by the assembly disclosed in the first mentioned document.
Category 5 specification for crosstalk performance is 40 dB at a frequency of 100 MHz, whilst for Category 6 this performance raises up to 54 dB. The main problem with the known assemblies or connectors is that, due to the higher performances asked for Category 6 with respect to Category 5, it is necessary to specify the plug performance additionally to the specification of the jack performance. It is thus necessary to specify very exact values also for the characteristics of the plug. Moreover, due to the close relationship between the plug and jack specification, the interoperability may not be guaranteed for Category 6 connectors of different productions. If low crosstalk plugs and jacks are designed as Category 6 products, then mating a Category 6 low crosstalk plug with a Category 5 jack can produce a connection that does not even meet Category 5 requirement, and vice versa.